1. Technical Field
The present invention relates to a virtual image display apparatus, such as a head mounted display worn on the head.
2. Related Art
As a virtual image display apparatus that allows formation and observation of a virtual image, such as a head mounted display, a variety of apparatuses that guides image light from a display device through a light guide plate to the pupils of a viewer have been proposed in recent years.
For a virtual image display apparatus of this type, see-through optical systems have been proposed to superimpose image light and external light (see JP-A-2006-3879 and JP-A-2010-224473).
However, since the apparatus described in JP-A-2006-3879 or any other document achieves a see-through configuration based on a pupil division method in which a light guide optical system having a light exiting aperture smaller than the size of the pupil is used, it is difficult to increase the size of a displayed virtual image. Further, a light guide optical system having a light exiting aperture smaller than the size of the pupil is used, it is difficult to increase an effective pupil diameter (light introducing diameter that allows virtual image to be captured and also called eye ring diameter) in order to support a variety of human interpupillary distances. Moreover, since the light exiting aperture of the light guide optical system and an enclosure are physically disposed in the vicinity of the pupil, a blind spot is produced and the resultant configuration is not perfectly see-through.